Study on physicochemical parameters and benthic macro invertebrates of Panimuhan stream of Shivapuri National Park

Abstract

Shivapuri National Park (ShNP) reservoir is a major source of water for Kathmandu Valley providing 35.6 million liter per day. In the present study period of six months from July-December physicochemical parameters like velocity of water, pH, temperature, total solids (TS), total dissolved solids (TDS), total suspended solids (TSS), dissolved oxygen (DO), free carbon dioxide (CO2), total alkalinity and total hardness (calcium and magnesium) were assessed and furthermore benthic macro invertebrates were also explored. Among the three sites, the first and second site were inside the ShNP at altitude of 1700 m and 1610 m respectively and the third site was at altitude of 1500 m outside the ShNP. Water velocity and temperature was conducted at the sites whereas other chemical parameters were performed at Natural Products Research Laboratory of Nepal Academy of Science and Technology (NAST). The current of water was measured by surface float method and the highest velocity was 1.0 m/sec at site 2 in July and the maximum temperature was 21 oC at site 3 in August. The pH 7.5 was found at sites 2 in July. TS was determined by residue left after evaporating unfiltered sample water and found value of 1900 mg/l at site 2, TDS was determined by residue left after evaporating filter sample and found average value of 1500 mg/l at site 2 and 3 and TSS determined by difference between the TS and TDS and the average was 400 mg/l at site 2 and 3. Similarly the maximum DO concentration was 9.32 mg/l at site 2 in November. The highest free CO2 concentration was 13.2 mg/l at site 1 in July. The maximum total alkalinity was 70 mg/l at site 2 and 3, the highest total hardness was 34 mg/l at site 3 in December and finally the highest concentration of calcium and magnesium were 10.42 mg/l at and 2.43 mg/ l respectively at site 3. Similarly, the benthic macro invertebrates of Panimuhan stream were identified by using sieve of 500 µ and 20×20cm size quadrate and 54 samples were collected and were preserved in 80% of alcohol. Altogether 32 taxa belonging to 9 orders, 29 families and 28 genera of benthic-macro invertebrates were reported. Among them order Ephemeroptera (28.6%) was highly dominant in all the sites followed by diversified Tricoptera (25.5%), and Placoptera (14.4%). Diptera (13.3%) was followed by Tricladida (6%), Odonata (4.4%), Stylommatophora (2.8%), Neuroptera (2.5) and finally Coleoptera (2.1%) which was least dominant group. And site 3 comprised the higher number of species i.e. 37.05% ( = 1.75) and the values of evenness (e) were 0.52, 0.40 and 0.51 at sites 1, 2 and 3 respectively demonstrated that the species were distributed in similar pattern in all the three sites. During the study period site 3 was found mid pollutant due to domestic wastage where people should be aware of negative impact of natural river water pollution. However, overall physicochemical components and abundance of benthic macro invertebrates depict the non pollutant condition of the Panimuhan stream of Shivapuri National Park in the year 2007.